56 591。3 55：L．763（958） Some Cretaeeous Peleeypods from Afghanistan by Yukio Y’ABE＊ Abstract Pelecypods，echinoid，ammonite，brachiopod and tetra・coral fronl Afghanistan were sent to the Geological Survey of Japan－through Dr。H．Sawata by the request of the GeologicaL Survey of Afghanistan，Royal Afghan Ministry of Mines and Industζies． Conceming the Pelecypods only，tねe writer determined their genera and speci丘o names‘as fQllows＝ 〈磁h6α4％初吻600s渉α如（SOWERBY） 加ooθ辮％％s aff。6擁zヒ％3BOEHM P’6グ0’7忽o％虎z （P）sp。．in（iet． 、 “P6・嬬”sp．．indet． L痂伽・rC卿伽θgen．etsp．indet． All of them obviously indicate the late Cretaceous period，except the i！lustrated speci－ mens under a name of P！ozo’7忽o％宛（P）sp．．If just・mentioned specimens represent actually the genus P’θ70吻㎏02z宛，this genus has a great probability represented the lower horizon than． the upPer C士etaceous， 、Int「oduction and Acknowledgements The distribution of Cretaceoug strata in the northem realm of Afgha－ nistan has been hitherto known，though玉ts detail has been scarcely reported。 Fortunately，the Afghan fossils belonging to pelecypod，echinoid，ammonite．’ brachiΦod an（i tetra－coral collected by the Geological Survey of Afghanistan， Royal Af宮han Ministry of Mines and Industries，were。sent to the Geqlogical Survey of Japan through Dr』H．Sawata who is carrying on the geolo＄ical reconnaissance in Afghani＄tan by the request of the Afghan Govemment． in ordβr to serve those for determination of the geological age・ In this、paper，the writer deals with only the pe1¢cypods representing theupP“rCretace・usperi・d，inc・nsiderati・n・f・thege・1・gicage・fthese fossils for an aid of studying th6pelecypod．fauna of Tethys sea。 At last，the writer wishes to express his sincere thanks to the Ge6一， 10gical Survey of Afghanistan，Royal Afghan Ministry of Mines and Indus－ tries for it＄ kin（i favours sending these fossils an（i offering an oPPortunity of this study to the writer． N6tes on P鍼eontology an｛l Geology Of the、pelecypod fossils6xamined，「the f6110wing two specific names were identified，but those of other six specimens could not be determined owing to i11－preserv母tion。 Among the determined species，加066名α郷％s伽1！σ6％s，〈吻渉h詔g％伽卿ε． 60s翻α，and their allied species are world－widely’distributed in the upper Cretaceous period，and are very effectivQ for the age determination．The geologicτange of the first．is thought to be sho茸er than that of the second・ 加06召盟卿％s枷1∫翻s and its、allied species are yielded from the Senoni4n（s，s．〉 ＊ Geological Dhpartment 27一（287） 地質調査『所月報（第10巻第4号） Name Locality N．34。860，E．67．280，N．34．860，E．67．81Q， ハ励hθα卿初卿ooos’σ如（SOWERBY＞ N．34．87。，E。67．180 動oo6劣α吻％s aff．枷1あ6％3BOEHM N．34．87Q，E．67．180 L砂加sp． N．34．860，E．67．280 ．P卿o款忽o物（P）sp．indet． N．34．820，E．67．540 （including－two spedmens） “P60惚％” sp、indet． N．34．870，E．67．180，N．34，860，E．67．28Q （including two specimens） L勿蜘86rCσ』励磁6gen．etsp．indet． N．34，860，E．67。280 to ∋》laestrichitian of Southern India， Europe， Japan， etc．漉露h6σgz房多zgz昭一 ・60s伽㍍and its allied species have・been repeatedly reporte（玉 throughout the upper Cretaceous deposits of Southern India，Southem Africa and various ・comtries of Europe，In this sense，these species seem to play an important role in the faunal relationship of the upPer Cretaceous period＆mong Europe， 、Southem Africa and Asia． The report on geology of Afghanistan in detail has been hitherto scarcely published．Acc6rding to the compiled geological map of Eurasian 、continent published in U．S．S．R．（1956），recently discovered localities of these fossHs are kept as a bla血k territory in this compiled map．Fortunately，the writer has an opportunity to read the article on the stratigraphical outline of Afgh副stan lately reported by S．PopoL and S．W．TRoM♪（1954）．Ac． ・cording to them，the Cretaceous system is widely developed from the north－ eastern to the southwestem rea1血s of Afghanistan．AmGng the Cretαceous， theSen・nian（5・1・）representsthenarr・Westdistributi・n・Regardingthe Senonian，strata，they say as follows： Senonian and Lower Eocene beds seem to be absent in Afghanistan except in the section north of the massive Turonian limestone at Tashkurgan and below the Argane pass （20セm W。of Kunduz，in the north“astem plain）。Both micro－and macr6－fossil studies con一 五rmed our assumption in the field that the marly串ections above the massive Turonian Iimestone repr“sent a Senonian section，near Tashkurgan gradually changing into L Eocene ．gypsiferous marls． This so－called“Tashkurganseries”iscomposedofa270m thickgでey くin the sun grey）marl section near the bαse composed of white weathering gregnish marls． ．About80mabove』thebaseathinsectionofblackoilshalesoccurs．Inthelshpushtaregion， in the Central Hindu．Kushン the Turonian massive limestone are covered by brownish gr6y （greeninsun）mar1乳withsandst・neandlim曼st・neintercalatipns，．whichals・mayrepresenta、 Senonian or L．Eocene section． As shown ill Fig．1，recently discovered fossil localities are situated at the northem and northwestem parts of Bamian in the Central Hindu Kush range，and the matrix of each fossil is composed of various colored sandstone。Therefore the approximate horizon of these fossi1＄may be in sandstone intercalation within brownish grey marls『which are assumed by them to be the Senonian or the lower Eocene．Meanwhile，when th6geolo－ gical age is inferred from these・fossils，the conclusion Will be deduced as follows l．It cannot be said frOm t恥e past studies of many authors that 漉露h6呵吻9％6・・吻㍍ranges・nly．intheSen・nian．且・wever，thege・1・gic horizon of lgcality①・（Fig．1）is thohght at least to becorrelatedtothe Arrialoor group（Upper Senonian＞of the Southem India and the upper Yezo group（from upPer most Senonian（s．s．）namely，Campanian tQ lower Mae一 28一（288） Scme Crelaceous Pe！⊂（）ypcds from Afghanistan 6〆 6860 翻 惣π 1 ηz2 乃ス3 7｝7融 ヒ u 1 5 3 斥 口1 DAUNG RUSTAN oFAIZABAD 口 KUNDUZ JURl4τ MAZAR一 SHARIF o o 口 TASHKU届罵 ロKHANABへD xし八RGANAP」ss 塾 口 Hへ15AK 3δ ≧ 『1 SA旧HAN 71 G日0民DAN 冥 雑 口 35 A州AN KへBUL k 一 口JAしALAB〈D 馴 も 34 ／ ＼ ト ゼ 33 o MUKUR マ → の α 隔雄6σ 9グ吻グ6・・鋤な，／〃・6の〃螂 仔． 如あイ必5， ㌘60オ8／～” Sp。 『 ② 舵ど訪躍 9盈卿」60鋤畝∠卿グsp・， ”磁・ご8々”sp、 「！1 ③ 伽煮・かく9・吻 sp・ ④ 〃3～ごカ6α 9グ吻〃6605オσ乙σ 『 O IOO ook吼’ F19．1 Map sho脚ing several localities of some Cretaceous pelecypods in Afghanistan strichitian）of Japan，as this locality yields〈彰鋤6σ9％初卿600s観αwith． 動066耀卿％saff。わσ1あo％s。Thelocalities②and④yieldingo孕1yハ擁h6σ g漉燭鰐60吻諭mayτepresent the lower horizon than the Senonian，but the writer assumes t五ese fossils to be also the Sen6nian．丁五e locality③yield． ing pi6zo地go勉α（～）sp．may possibly represOnt the IGwer horizon than the Sen⑩an（seep．34）・ Desα直p樋on of Spec五es ，Genusハ観♂h20：DRouET，1824 Nei撒ea lquinq旺eeosねta（SOWERBY） （Platel，行gs．1～4） 1814． P66勧g％吻κ660ε∫伽s SowERBY l Mineral Conchology of Great Bri一 ．tain，Vo1．1，p．122，p1．56，figs．4～8 1846． 1σ勉辮卿伽σ％600sめ如D’ORBIGNY l Paleontologie fra．ngaise，Terra．ins cr6tac6s，VoL31p．632，p1．444，丘gs．1～5 1846． P66顔z卿初卿600ε臨！％s PlcTET et Roux l Description des Mollusques’ Fossile3，P．296，pl．45，F丘gs．3a～c 1870． P60渉6％g媚4πoo5如劾s・CREDER l Deutsche。geo1．Ges“11．Zeitsch．，Band 22， p． 232 1871． 9Vol4㈱％卿600ε渉伽，SToLlczKA l India．Geo1．Survey Mem．，Pa1。、 29一（289） lll 地質調査所月報（第10巻第4号） 曽 Indica，Cret．Fauna Southem・India，Vo1．3，p．437）p1．31，figs』 1～6；p1．38，figs．4～9 一 ・ 、 巨 1885．・〈擁h餉g％珈％ooo吻≠αWHITFIELD；U．S．Geo1．Survey Mon．9，p．．56， P1．8，丘gs．12～！4 －1903．P66伽（惚励6α）4痂卿oo吻！％s WooDs l A Mon．Cret．Lame1L Eng－ 1and，Vo1．1，p．202，p1． 39，figs．14，～171p1．40，figs．1～5，T Palaeont．Soc．London ■908．．P60痂（ハ励h召σ）9伽9観o吻加WooDs l Amals south傘frigan Mus．， VoL4，pt．12，p．’298，p1．35，fig．14 ■914． P召6彪％g％伽g％660s殉∫z‘3STEPHENsoN．ヂU。S．G，S．．Pτof。P亀per81，p。241 tabs．2～9 F1916．P66伽 9％吻％卿吻劾3GARDNER；Marylalld GeO1．・Suτvey，UpP6r Cretaceous，p．596，P1．34，血9．10 ■927．P60伽9痂卿60s鰯％s WADEl U．S』G．S．Prof．Paped37，P．64，P1． 21，．丘gs． 1～5 ユ950．地励6α9％伽9％600s！α㍍CoLLIGNoN l Annales G6010gique du Service de Mines，，Madagascar，Fasdcule NO．17，p．31 All s口eci血ehs are right valve． The test remains only in one speci－ men，and others are all internal moulds。 The right valve ovately subtrigonal e文clu＄iye of auric16s，nearly equi一 ユatera1，usually a little－higher thlan lqng，regularly－an（1．well sw611en with －very prominent umbo l・maximum“onvexity lying at about one－thirds from the umbo in the height of she11． 塗 P加6％5加S（in’mm） Height ．Len墓th ．HIL P1．1，Fig．1 52．0（ca．） 48．5（ca．） 一1．07 P1．1，Fig．一2 46．0 39，0（ca．） 1ユ8 Umbo Iocated at the middle of the she111engthジvery protruded，pointed ”beyon（i the hinge－1ine，incurved，orthogyrate or slightly prosQcline． Both －dofsal margins feebly concaved，diverging at angle・of about800． Both auri－ des qistinctly；differentiated with the discl Surfa』ce scul）tured with．five， ．．elevated，round－topped primary radials，subequal in size and intercosta1 二spacing，existi血g three or、rarely four，equal and regμlar secondaries between ．e母ch pair of primaries，but、the antero－dorsal part in Ithe disc omamente（1 ・with rather fine close．set radial ribs．Dental feature unknown． 06s6廻襯o％and R翻α嬬sJ Few specimens with poor preservation』afe ・available for the writer；they lack・external sculptures of b6th a．uricles， ユigamental and umbonal areas． M母ny authors have hitherto stated their opipioカs conceming thfs ．species，．because this species has tolerably．wide range of the variation， namely，in the’numbers，shape and interspaces of the secondary rib8． 』Unti1』the beginning of the20th Century，these factor＄h皐（i been thought to play an important role in the distinction of another species．Then，from ・the plates皿ustrated by many奪uthors，it was e琴ami血ed by the writer how many forms are there，in many specimens identified undera name of IV6歪一 ．功6σσ％吻卿660吻㍍』In this case，the writ6r neglected the above．mentioned factor＄，bec亀use SToLlczKA15）and WADE16）pointed out that tllere was little